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Release 5.2.28 on 6/10/2011
2011-09-13 17:44:24 +00:00
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The DbMpoolFile Handle
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<h2 class="title" style="clear: both"><a id="mempset_mp_max_openfd"></a>DbEnv::set_mp_max_openfd()</h2>
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<pre class="programlisting">#include &lt;db_cxx.h&gt;
int
DbEnv::set_mp_max_openfd(int maxopenfd); </pre>
<p>
The <code class="methodname">DbEnv::set_mp_max_openfd()</code> method limits the number of file
descriptors the library will open concurrently when flushing dirty
pages from the cache.
</p>
<p>
The database environment's limit on open file descriptors to flush
dirty pages may also be configured using the environment's
<a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. The syntax of the entry in that file is a single
line with the string "set_mp_max_openfd", one or more whitespace
characters, and the number of open file descriptors. Because the
<a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is read when the database environment is opened,
it will silently overrule configuration done before that time.
</p>
<p>
The <a class="xref" href="mempset_mp_max_openfd.html" title="DbEnv::set_mp_max_openfd()">DbEnv::set_mp_max_openfd()</a>
method configures a database environment, not only operations
performed using the specified <a class="link" href="env.html" title="Chapter 5.  The DbEnv Handle">DbEnv</a> handle.
</p>
<p>
The <code class="methodname">DbEnv::set_mp_max_openfd()</code> <span>
<span>
method either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</span>
</span>
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<div class="sect2" lang="en" xml:lang="en">
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Release 5.2.36 on 9/14/2022
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<h3 class="title"><a id="id3627302"></a>Parameters</h3>
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<div class="sect3" lang="en" xml:lang="en">
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Release 5.2.36 on 9/14/2022
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<h4 class="title"><a id="id3627291"></a>maxopenfd</h4>
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</div>
</div>
</div>
<p>
The maximum number of file descriptors that may be concurrently opened
by the library when flushing dirty pages from the cache.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
Release 5.2.36 on 9/14/2022
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<h3 class="title"><a id="id3627320"></a>Errors</h3>
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</div>
</div>
</div>
<p>
The <code class="methodname">DbEnv::set_mp_max_openfd()</code> <span>
<span>
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors:
</span>
</span>
</p>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
Release 5.2.36 on 9/14/2022
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<h4 class="title"><a id="id3627373"></a>EINVAL</h4>
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</div>
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</div>
<p>
An invalid flag value or parameter was specified.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
Release 5.2.36 on 9/14/2022
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<h3 class="title"><a id="id3627351"></a>Class</h3>
Release 5.2.28 on 6/10/2011
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</div>
</div>
</div>
<p>
<a class="link" href="env.html" title="Chapter 5.  The DbEnv Handle">DbEnv</a>, <a class="link" href="memp.html" title="Chapter 9.  The DbMpoolFile Handle">DbMpoolFile</a>
</p>
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<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
Release 5.2.36 on 9/14/2022
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<h3 class="title"><a id="id3627253"></a>See Also</h3>
Release 5.2.28 on 6/10/2011
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</div>
</div>
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<p>
<a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools and Related Methods</a>
</p>
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